Tony,
Being serious for a moment, I'd say it's nothing more than personal bias. I've been a Tannoy fan since the late seventies, since a former friend of mine demoed a pair of large Tannoys against Bose 901s. At that time the Bose were about three times the price and the said friend was a hifi dealer and tried to tell me just how great they were compared to the Tannoys.
I personally thought how great the Tannoys sounded and how wonderful it would be if I could afford them. Incidentally I became a BMW fan around the same time
. Since then I've heard many many Tannoys and to me they sound "right". The Westminsters were just something else.
This does not mean that I think they are the best speakers ever. I could quite happily live with a number of makes, but I feel an attachment to Tannoys. The bigger the better. I also love the styling of the TD12s and the craftmanship of the Prestine range, my favourite would probably be the Canterbury's.
There you go. No logic, just pure prejudice. Sad or what?